NORTH TEXAS (CBS 11 NEWS) – An estimated $450,000 in jewelry, stones and precious metals that disappeared in the mail, has been connected to a U.S. Postal Service delivery truck driver in Fort Worth.

A federal judge accepted a guilty plea from Hubert McDonald this week, after an investigation that lasted more than two years.

Federal court documents say packages sent to Fort Worth from Cash America pawn shops all over the country started disappearing in June of 2011. The packages were never seen again once they left the USPS Processing and Distribution Center on Mark IV Parkway. Investigators discovered McDonald was the truck driver on duty when the packages disappeared.

In December 2011 special agents from the USPS Office of Inspector General watched McDonald drive off his truck route and go to his home.

Later that month, they put a GPS tracker on his personal truck. Two days after a package disappeared, they tracked his truck to an apartment complex in Benbrook, then to a pawn shop in Fort Worth, where someone sold 52 pieces of jewelry and 165 coins, for a total of $1,989.

Between August 2011 and January 2012, investigators found 29 other pawn transactions. In that time McDonald deposited $42,400 into his bank account, while making just $16,681 from his job at the post office.

When investigators searched his home in March 2012, they said they found two gold watches, and $8,000 in cash.

Court records show McDonald was going through a bankruptcy in the months before the thefts started. He pled guilty to one count of possession of stolen mail.

Attorney Brian O’Shea said Friday the heart of the case is the sentencing, which won’t happen until February.

The U.S. Attorney’s Office, USPS and Cash America declined to comment, pending the outcome of the sentencing.